I'm trying to make a 90s styled first person dungeon crawler in GameMaker sort of like the older Shin Megami Tensei games (or any other first person dungeon crawler came out in the era of SNES or Genesis) What I'm trying to include is,
- a HUD
- an inventory system
- a turn based battle system
if anyone can help, please do. Thanks
Every single one of these suggestions is worthy of its own topic. You should probably ask each question individually as it comes up for better answers. I'll just respond to the "90s styled first person dungeon crawler" one since it's the main question implied by the topic title. I'm probably among the most knowledgeable about doing first-person dungeon crawlers in GM considering that's basically all I've been doing in it for literally over a decade.
Before I go into anything, I noticed you have your topic tagged as "Legacy GM." Which version of GM are you using? If it's pre-Game Maker Studio, prepare yourself for an absolutely miserable experience. Having successfully completed a very barebones dungeon crawler in GM7, it's just so much of a hassle. Versions up to GM8.1 have so few organization features that it essentially quadruples your workload keeping your massive codebase from becoming a mess of illegible spaghetti. I would highly,
highly recommend doing yourself a favor and going with the latest version of Game Maker Studio 2, 2.3. Even older versions of GMS2 are painful given how much better suited v2.3 is at allowing you to organize the data-heavy structure of RPGs. Things like HUDs are also significantly easier to do in newer versions of GM.
Now, onto dungeons. The first thing you need to do is ask yourself what kind of dungeon walls you want. There are plenty of terms people attach to the two main types used in these games, but I'll just use
Block and
Line. Block walls take up an entire cell on the map grid. Examples of games that use this style of wall are Etrian Odyssey, Shining in the Darkness, and Legend of Grimrock. Line walls take up the space between cells on the map grid. Examples for this style include Wizardry, Shin Megami Tensei (what you're looking for), and basically every single PC RPG before the 90's. The former is only slightly easier to create maps for in GM, but I find it feels like dungeons are overly bloated in turn-based RPGs. Both are still easy to work with in the room editor, though.
...however, that's just for setting up the data. Drawing that map to the screen is a whole other matter. This particular case is one where making a 2D game is
leagues harder than making a 3D one. It's much easier to get a simple 3D engine up and running than to pre-render walls for
every single position possible, and then do it all over again if you want visible forward movement, AND THEN AGAIN if you want smoother turning like SMT does. In fact, going 3D is what I did for my first dungeon crawler. I followed a simple FPS tutorial (I'm sure some of the older folks here remember fps1.gm6/gmk), then adapted it until it was completely unrecognizable.
This is what I would absolutely recommend as a starting point. You don't even need to have any experience with 3D modeling. The walls, floors, and ceilings can be rendered in full 3D while everything else can stay as a 2D sprite. I have no idea how to do this in current versions of GM, so I suggest looking for a tutorial. I do not recommend doing 2D as a beginner. It's a lot more complicated than it may seem on the surface.