KAIKAN is a focused vertical-scrolling shoot ’em up that embraces the fundamentals of old-school arcade design while introducing enough scoring complexity to make repeated play increasingly rewarding. Developed and published by zakichi, the game revolves around fighting through five stages with six different aircraft, each possessing its own weapon characteristics and tactical advantages. Rather than attempting to impress through an enormous campaign or elaborate narrative, KAIKAN concentrates on responsive shooting, enemy destruction, survival, and the pursuit of increasingly efficient high-score runs.
At first glance, the action is easy to understand. Enemy formations appear, bullets begin filling the screen, and the player must destroy everything possible while avoiding incoming attacks. Beneath that familiar structure is a surprisingly involved item system. Eliminated enemies release bonus items, and continuously collecting them raises their rank and therefore their scoring value. Missing an item reduces the rank and triggers a penalty condition that temporarily changes how progression works. Consequently, maintaining a successful scoring sequence becomes almost as important as staying alive. The player is encouraged to move aggressively enough to secure valuable pickups without recklessly entering dangerous areas.
One of KAIKAN's most interesting mechanics is the ability to manipulate bonus items through the firing controls. Releasing the shot button attracts nearby items toward the aircraft, while firing again causes attracted items to resume falling. This simple interaction creates an unusual relationship between attacking and collecting. Constant firing is not necessarily the most efficient strategy because temporarily stopping can help secure valuable items. Experienced players therefore have to develop a rhythm between shooting, positioning, collecting, and dodging. What initially appears to be a conventional arcade shooter gradually reveals itself as a game built around carefully managing several interconnected systems.
Bombs are equally important. Normal bonus items contribute toward a bomb gauge, eventually providing a bomb that can be stored. Holding one offers additional protection because receiving a hit can activate an automatic barrier, sacrificing the bomb instead of immediately leaving the player defenseless. Manually activating the bomb has significant offensive and scoring benefits, however. Enemy bullets caught in its effect become special bonus items, while enemies struck by the explosion can produce additional bomb-related rewards. These special items are worth more than ordinary pickups and increase a separate counter, turning bombs into strategic scoring tools rather than weapons reserved exclusively for emergencies.
Boss battles take advantage of these mechanics by connecting the accumulated counter to time and scoring opportunities. Destroying bosses and their individual components efficiently can produce valuable rewards, while boss-related items contribute toward the BOSSMEDAL system used during the final confrontation. This gives earlier performance consequences later in a run. Players who simply want to finish the stages can approach these mechanics more casually, but high-score hunters will need to understand how item collection, bomb usage, boss destruction, and medal accumulation influence one another.
The six aircraft add another substantial layer of variety. Type A specializes in explosive napalm attacks, while Type B offers a wide shot suitable for covering large areas. Type C uses homing weaponry, Type D spreads fire across much of the battlefield, and Type E emphasizes powerful blast attacks. Type F is particularly distinctive because its rotating ball can erase enemy bullets. Weapon behavior also changes during low-speed movement, meaning aircraft selection affects much more than appearance. Learning the strengths of each machine can dramatically alter routes through stages and approaches to enemy formations.
The Steam edition also contains numerous changes compared with the earlier free version. Aircraft performance was adjusted, horizontal free scrolling was removed while the visible play area was widened, and indicators were introduced to make falling scoring items easier to track. The player's location can also be displayed on the mini-map. Two previously hidden aircraft are available from the beginning, while rules surrounding the true boss encounter were modified. Once players have reached that battle, it becomes available for practice, although achievements associated with defeating it cannot simply be earned through practice mode. Continuing is also prohibited after entering the true boss fight, preserving the significance of reaching and overcoming the encounter during a legitimate run.
Presentation improvements include replaced background music, controller vibration support, revised visual effects, and optional adjustments to blur effects that could interfere with gameplay visibility. Steam leaderboards are an especially natural addition because competitive scoring is central to KAIKAN's longevity. Achievements and practice functionality provide additional objectives, while Steam Cloud support makes repeated progression more convenient. These additions demonstrate that the commercial Steam edition was treated as a revised version rather than merely an unchanged rerelease of the original game.
Visually, KAIKAN favors straightforward retro-inspired pixel graphics and functional battlefield readability over elaborate spectacle. That approach fits the experience because the important information involves enemy locations, projectiles, collectible items, aircraft positioning, and scoring opportunities. Its five-stage campaign is undeniably compact, so anyone looking primarily for a lengthy adventure may find the amount of conventional content limited. The intended longevity instead comes from mastering those stages, experimenting with six aircraft, reaching the true boss, earning achievements, and continuously improving leaderboard scores.
Ultimately, KAIKAN succeeds as a tightly designed arcade shooter because nearly every mechanic contributes to the central pursuit of better performance. Destroying enemies is immediately satisfying, but learning when to stop firing, attract items, deploy bombs, manipulate bullets, attack bosses, and protect scoring chains gives the experience much greater depth. Its limited stage count prevents it from feeling expansive, yet its mechanical density compensates through strong replayability. For players who enjoy traditional shoot ’em ups, bullet-heavy encounters, score optimization, and gradually mastering demanding systems, zakichi has created a small but impressively purposeful arcade experience.
Rating: 7/10
