Agony

This horizontally-scrolling shoot 'em up features six long levels, all with detailed and mellow background graphics, aiming for a less hectic feel than contemporaries such as Project X. As a magician's apprentice, you have been turned into an owl to give you the best chance of destroying the many dark creatures to be faced, and thus discovering the secret of cosmic strength.

These dark creatures include piranhas, giant ants and mosquitoes. Extra weapons and invincibility periods can be collected. The technical details include 3 layers of multi-directional parallax scrolling, background animation, and different title and in-game music. Source: IGDB