What is the absolute difference between Chopin's work and Liszt's work?

In a word that the difference between chopin and Liszt, it is innovativeness or conservativeness. Chopin had strong tendency to limit his sphere of activity and set very strict rules to compose music but Lizst always explored new possibilities of music and performance. There is clear difference between their works composed by both great artists on this point.

Chopin always pursued the perfection of each works but he would never protrude the frame he set that he had found by piling up ancient composer's wisdom. On the other hand, Liszt unprecedentedly broke the existing rule of music theory to pursue develop new category of music. Actually there were a lot of failed work he left as well around the world.

The difference of religious aspects

On more important thing to interpret the difference between both two great artists, I cannot explain besides their religious viewpoint.

Chopin's work require great delicacy to players because his conscious is kind of embodiment of aesthetic sense, however his work doesn't strongly make us feel the background of religious aspect. On the other hand, when you play or listen to Liszt's work, you will not be able to ignore his sense of religious viewpoint. His real intention of Etude works of Études d'exécution transcendante is fundamentally getting your spirit much closer to the territory of the God so finger technique is only one of additional factor against his religious viewpoint, therefore when you play Liszt you must 　be conscious of the relationship between the works and religious aspect

About their relationships with women and how this matter reflects on their works.

The fundamental difference of viewpoint of relationships with women between them is whether being protected by woman or taking advantage of woman's protection. Chopin was the former one and Liszt was the latter one. And Chopin tended to have slightly relationship with man, whose factor indicated his complex about a lack of manliness so his work sometimes require pianist to play more fierce and aggressively.

Chopin composed many works for his disciples who was big-built and had big hands so I thought he definitely had sex complex.

The difference of piano music theory

What they pursued about sounds of piano was totally different. Chopin's music was based on sing. Liszt's music was more like orchestration and in his later years, his direction of work was on the way to impressionism.

The difference of performance

Chopin's work exist the strict rule of extremely avoiding the technique of overhand crossing. Basically he composed music as playing the piano and made it rule not to write as difficult passage as pianists cannot play. Liszt also composed his music as playing the piano but he wrote the passage as he wanted even if it was quite difficult to play.