The term "Doom-clone" was originally applied to all first-person shooters, but Heretic is probably as much of a clone as it gets, to the point that it's hard to speak about it without comparing it to Doom.

They basically just took Doom and wrapped it into fantasy textures. The only major difference here is the ability to pick up items. They basically function as orbs in Doom, except now you can store them and use them when you actually want. The only item that makes a major difference is the amulet that lets you fly. Flying is probably the only really remarkable feature of Heretic and is the most fun that can be had with this game.

The level design is a mixed-bag. Episode 2 is largely solid. 1 and 3 have some truly atrocious levels that'll have you running around in circles trying to find a switch or a key. Especially in episode 1 this is a problem as there are plenty of doors that look like walls, forcing you to run around humping every walls you see.

Overall, it's a decent enough experience for 1994, when I imagine a Doom clone would've still been impressive, but it didn't age very well. At least it's relatively short if you only play the original episodes. Well, I'll review the expansion separately when I beat it.