No revenue estimate for GOG — its rating/review counts don't calibrate to sales the way Steam's do. The Steam version is estimated at $5K — a different platform, not this one.

Hordelord

Hordelord is a hi-octane arena mobility shooter (horde & endless modes) where you face waves of nasty enemies. Armed with powerful weapons and high-mobility skills, zip around and fight to achieve the highest score on global leaderboards. Hordelord sports tight gunplay, satisfying kills, and meaningful upgrades.   Features: Horde Mode: Beat a finite number of increasingly difficult waves of enemies. Endless Mode: Try to survive for as long as possible against endless waves of enemies. Get rewarded for your playstyle by performing spectacular kills or hard-to-achieve feats. 6 punchy weapons, each with its own uses, tactics, and upgrades. Unlock powerful alt-attacks for your weapons for even more carnage. Equip Tarot Cards to gain various boosts and synergies to fit your playstyle. Zip around using multi-jump boots, spectral shovel, and various environmental jumpers. Many enemies, each with distinct strengths, weaknesses, and behaviors.