A very good game if you want to experience an old-school FPS and even better with a bit of modding.
Heretic is one of the best games built on the Doom engine. It features the same fast-paced shooting as Doom and also has the same level system with coloured keys, items, secret places and even secret levels to find. If you've enjoyed playing the original Doom, you will definitely have a good time with this one. The weapons are very fun to use and, thanks to a special item, can have secondary attacks/effects. Since the Steam version runs on DOSBox, I highly recommend using a more modern frontend like GZDoom along with the great HD graphics pack released some time ago on Nexus which both make it really pleasant to play, even in 2021.
The enemy roster is rather limited and becomes repetitive quite quickly. Besides, while I really enjoyed the main game, I didn't really like what I saw of the expansion. I thought the level-design was a bit lazy and didn't have the maze-like feeling of the main game.
This review on Steam if you want to mark it as helpful.
By the dark gods, I remember playing this more than 20 years ago! This, the original Doom and a game called Blood. I didn’t it it was possible to still play it like this, with HD graphs and everything :D.
Yes, it still is. There are still competent modders who try to squeeze the most out of those classics. I played through Blood last year and it was great! Still have Shadow Warrior Classic to play through :)
Dosbox does wonders for letting you run these old games. Pretty much anything released for DOS runs at least as good in Dosbox as it did back in the days (and in my experience it runs far better). And quite a few games have got modern re-releases, like Blood and Duke 3D. Some of the older games also has source ports with all kinds of nice improvements. The DOOM-engine games are especially well supported in this regard (and Heretic runs on the same engine as DOOM)