-- monsters spawn in waves, increasing in difficulty
-- weapon strength/effectiveness increases with monster difficulty
-- two weapon slots (main weapon + WMD)
-- weapon upgrade means more projectile fired with each shot
-- weapons drop with each wave, instead of each monster
-- unlimited ammo, except for WMD
-- health increases from map to map
-- monster attack/health increases from map to map at a slower rate than player
well that's the idea anyway. maybe by new years ;)
it works better in 2D. in 3D it's just boring