To be able to melt metal stuff you need to find at least 5 red beam upgrades. There are 6 total. All their locations in this video guide.
All Red Gun Beam Upgrades
Timestamps
First of all, the game is really deserves to play it through with no guides, but if you really getting mad and cant find some upgrades, here’s the guide.
00:05 >> Gun Altfire Damage Upgrade #1
01:39 >> Gun Altfire Damage Upgrade #2
02:16 >> Gun Altfire Damage Upgrade #3
02:41 >> Gun Altfire Damage Upgrade #4
03:20 >> Gun Altfire Damage Upgrade #5
03:42 >> Gun Altfire Damage Upgrade #6
How do you get the white block out of the way of the entrance on that last one?
you need the strength upgrade.
find 2 green seeds then 2 soaked sponges add them at a drink station push the button and drink. and you’ll have the strength upgrade/ bonus