You might not have played Lands of Lore: Guardians of Destiny (PC)

The second part of the Lands of Lore series that was released in 1997 for the PC.

Gameplay: RPG, Story, Singleplayer, First Person

You are Luther. You have been accused of being a servant of the dark armies and imprisoned. You manage to escape because you are cursed to randomly transform into a tiny lizard or a huge demon. This curse is also the reason for the accusations. After your prisonbreak you will have to find a way to break the curse. 

The Game features a variety of different magic abilitys, weapons and mechanics due to the curse that lets you either be a tiny lizard, which enables you to go through small passages, or a huge demon, that can destroy anything in its path. The controls in this game are a bit iffy, as you will have to click on a button with your mouse to attack or cast a spell. But the game does not suffer too much from that considering the gameplay is not all about combat. A mayor part of the game is interaction with your environment to solve puzzles and that works like a charm with the mouse controls.

The game is fully voiced and has a quite charming retro soundtrack.

You can get the game including the first part of the Lands of Lore series in a bundle for 6$ on gog.