I actually have a very specific plan for developing Therium-2.
Here's what it looks like:
This is the time when I'll be making new levels, implementing new features, new textures, skyboxes, characters, paths and enemies. I'm basically making the whole game here. When I'm done, I'll have a mostly unpolished campaign with some bugs, plot holes and/or f****g stupid game or story design.
The Alpha stage will be done when every single level and path is finished and running mostly properly.
Once I'm done with Alpha, I'll be polishing the entire campaign. It'll look better, run better, have less stupid game design or plot holes (if any, hopefully) and probably so much dialogue I won't be able to count. The Beta Stage is over once me and any bug testers have found all the bugs present in Therium-2's gameplay and mechanics and the game is at a presentable state of quality or performance (AKA won't run horribly or look horrible).
Once I'm done with both Alpha and Beta, I'll be doing a review stage. Here, I'll get some gameplay testers to go through each level and play the campaign before it's released, and give me (or us if I somehow happen to have a team or something) feedback for how each level feels in gameplay (whether it gives them a certain vibe through asthetics or gameplay, how difficult it is, etc). Then, based on this feedback, I'll work the levels through again and try to beta test it again if necessary.
This will be the absolute least fun part of everything ever. In this stage, I'll try to optimize downloading Therium-2 as much as possible, meaning less dependancies, less of a pain to install in any way, more accessible, etc. I'll do this both before and after I release the campaign, meaning I'll optimize the installation process and dependancies, and afterwards, you guys just give me bug reports depending on what status you were in and such. I'll fix anything that I can that comes my way.
This won't be the final stage. In fact, this stage will be as infinite as whatever I feel like it being. From this stage on, the campaign is completely public and free for anyone to download. Every single level and aspect of the campaign will be accessible to people. What people will NOT do, but I can't stop them from doing, is loading a level they should already be loading. AKA: Skipping levels and cheating. You better not do this you guys, you can really spoil some stuff.