If you play on the "Normal" difficulty, you have to get EVERY inspiration pick-up (light bulbs) in the game in order to purchase every upgrade (there are 480). This can be very frustrating as I myself normally don't bother with collectibles as hard as some. I found a LOT (missed 10-12 or so I think), but not all.
But there is a trick if you've completed the game on "Normal", you don't want to collect every light bulb but you DO want to have this achievement. Although, you won't get the following achievement, which you WILL get if you collect all the lightbulbs (in order to be able to purchase all the upgrades):
What you have to do is the following (AFTER completing the game!): Clear all your upgrades (you can do that if you choose to mix it up again). Then go into the options, gameplay section an then activate the "Easy" mode.
Now you can go into the upgrades menu again. On "easy" all the reserve lives are already "bought", so you can spend all your inspiration on the other upgrades . Still you need 380 bulbs and you won't get the "Totally Inspired" achievement...
Here's the list of the cost of the different upgrades:
- Increase Blob’s starting lives to 2 – 5 bulbs
- Increase Blob’s starting lives to 3 – 15 bulbs
- Increase Blob’s starting lives to 4 – 30 bulbs
- Increase Blob’s starting lives to 5 – 50 bulbs
- Increase maximum size to 120 – 10 bulbs
- Increase maximum size to 140 – 20 bulbs
- Increase maximum size to 160 – 30 bulbs
- Increase maximum size to 180 – 40 bulbs
- Increase maximum size to 200 – 50 bulbs
- Increase Player 2’s ammo to 100 – 5 bulbs
- Increase Player 2’s ammo to 150 – 10 bulbs
- Increase Player 2’s ammo to 200 – 25 bulbs
- Increase maximum armor to 2 – 10 bulbs
- Increase maximum armor to 3 – 20 bulbs
- Increase maximum armor to 4 – 30 bulbs
- Increase maximum armor to 5 – 40 bulbs
- Damage charge cost to 60 – 10 bulbs
- Damage charge cost to 40 – 30 bulbs
- Damage charge cost to 20 – 50 bulbs