How do I know if "save" and "load" worked?

Ive used this tutorial

to make the checkpoints in my game.

But i have this problem.

When my player dies, i play "death" animation and then -> when "death" animation finish->load "mysave"

Most times works great but sometimes the player just stays there on the last frame of "death" animation.

The game is NOT frozen because i can access my pause menu and exit the level

On the last checkpoint, the animation changed so i thing save is completed.

If it failed to load the save, is there something i can do?

Could the problem be something else and not the save/load function of C2?

I use the latest NW.js and C2.

also there is a BIG framerate drop before this bug..

Im afraid it might be a problem with nw.js 0.24

Ive tried to downgrade to 0.23 but now not even preview is working.

Also, my game is already on steam.

If i manage to downgrade nw.js and export and update on steam, will it work for those who downloaded my game or it will not start like now (in preview mode)?

Leaving package.nw and nw.exe without doing copy /b did not help.

Also removing --in-process-gpu did not help either.

Player stucks at the last frame of death animation, If i fire the player's powerup, it fires like he was alive but no movement or respawn.

It has this issue after lvl5. Maybe on lvl9 or lvl6 or lvl11 and so on, but it never did it before lvl5.

I dont know if that rings a bell..