You can beat the game with the starting gear without upgrades. Hell, people did starter sword + shield runs on 4 boss cells and beat the game. It is a skill-based game. It just has random equipment/upgrades that can make the game easier. This does not change the fact that you can simply play well enough to not take damage. There are no enemies in the game that force you to get hit unfairly. If you do not get hit, you will eventually win.
"people did" = 1-5 people worldwide maybe .-) the game is cleverly made because it makes you think it is skill based when it is not...it is more about rolling around like a madman, collecting scrolls and items and that was it. hell you can even speedrun the game without killing any enemies, how is this skill based? there are no complex patterns which you must decipher to dodge, it tells you with a fat exclamation mark.
even an very casual player can go to the final boss in this game if he has the right upgrades.
you sir, are definitely under the topmost players with 8hours played and already running 1cell mode without probs, don´t underestimate that .-)