1946 started off the post-war Popeye period quite well. None of the cartoons from the series that year were classics and they had pretty much similar strengths and flaws. They did suffer from not being particularly original, with some previous Popeye cartoons being remade and somewhat too faithfully and Popeye had a temporary voice change that never quite clicked with me, plus Olive was wasted. They were though well made, scored and were entertaining enough.
That is the case with 'Rocket to Mars'. Notable for being the first animated cartoon to depict alien invaders and the theme of alien invasion, it is an enjoyable Popeye cartoon but there is not an awful lot mind-blowing. Loved the setting and the premise which sounded different, but an opportunity was missed to do something more with them and do something more origjnal. Promising set-up but becomes too standard Popeye territory, don't get me wrong standard Popeye is not a bad thing but one does wish for something fresher once in a while.
'Rocket to Mars' is very well animated, do think it is one of the best-looking 1946 Popeye cartoons. The landscapes especially are so vibrant and atmospheric and the shots help make them even more impressive, especially in the first half. Every bit as good is the music, lots of merry energy and lush orchestration, adding a lot to the action and making the impact even better without being too cartoonish.
Popeye himself is easy to like and has good comic timing. Bluto, in martian form (another reason to see the cartoon for, am not kidding) is a funny and formidable adversary and the two sparkle in their chemistry together. The martians have the right amount of amusement and creepiness. 'Rocket to Mars' is amusing, Popeye and Olive's chemistry is charming and the set up is promising. Jackson Beck voices robustly.
Unfortunately, didn't find that everything worked here in 'Rocket to Mars' here. The conflict tends to be too predictable and easy, basically Popeye vs Bluto in space with martians, with the outcome never in doubt and things resolve too on the convenient side. Olive has next to nothing to do.
While Harry Welch gives Popeye a good go and did so for all the cartoons he voiced the character while Jack Mercer was serving in the military, it always felt strange without Mercer having so closely associated the role with his voice. Mercer fits the character design much better and has more energy. Mercer though does return here for some of the voice work and his contribution is great, though when comparing the two the difference in quality is quite big and jars a bit somewhat. It would have been better if one or the other voiced.
In summation, decent but nothing exceptional. 7/10