So am I able to get the rune in the Ossuary every time or only sometimes? Cos I couldn't get it when I tried earlier.
You should always have it after getting it the first time. It's a permanent upgrade.
So I had a really good run, beat the time guy (really easy) but died at the second last area. You can finish the game (beat the final boss) without even opening half of the game's areas?
There is multiple paths to each boss, some of which can't be opened until you get the permanent upgrades.
While you could technically finish the game and beat the final boss while only seeing....roughly half of the areas, after you beat the boss the first time you get a Stem Cell which lets you modify the difficulty....beat it a second time, you get two Stem Cells and regular Cells drop 2x as much, etc. You can get up to four Stem Cells which also opens more options on which areas you travel through, and increases the number of Cells that drop. This is especially useful if you're upgrading the Legendary Forge because the second upgrade is like 3,000 Cells and I think the last one is 8,000 Cells.
Also keep in mind they're going to keep adding areas, weapons, monsters, etc. They're working on an expansion right now.
Fred.